使用PHP中的PDO基于主键读取MySQL数据库

My code doesn't seem to work. I'm using the following:

$statement   = $db->prepare("SELECT * FROM carts WHERE (order_id = ':order_id')");
$result      = $statement->execute(array(':order_id' => $order_id));
$result      = $statement->fetch(); 

Which returns a boolean according to gettype($result); print_r($result) simply displays Array, though this is not expected. The data I'm reading is:

So I should expect an Array to be returned, not a Boolean. The PDO is correct and working, as I can call a write command. What's the best way using PDO to read a row based on the Primary Key order_id into a parsable array?

And as a split, is there a more efficient way than SELECT * WHERE to read a single row of data from a TABLE when the data is based on the Primary Key?

before all, set properly your error mode. If you can run the query with single quotes without an error popping, set this:

$db->setAttribute(PDO::ATTR_ERRMODE,PDO::ERRMODE_EXCEPTION);
$statement = $db->prepare("SELECT * FROM carts WHERE order_id=:order_id");
$result = $statement->execute(array(':order_id' => $order_id));
$row = ($result ? $statement->fetch(PDO::FETCH_ASSOC) : array('problem' => 'with your query'));
print_r($result);

PDO fails with single-quotes around parameters. check your $result for the return value of execute(). you may have to specify a fetching mode for the fetch. depending on your sql database, parenthesis around the condition may also cause the query to fail.

you have to store the result in somewhere, add:

$rows = $statement->fetchAll(PDO::FETCH_ASSOC);

next to $result = $statement->fetch(); to store in $rows the data returned